Strip feeding for sound and sound picture systems



H. FRIEMEL Nav. 26, 1940.

STRIP FEEDING FOR SOUND AND SOUND P ICTURE SYSTEMS Filed April 9, 1937 3 sheets sheet 1 INVENTOR H. FR/EMEL i-HJW ATTORNEY H. FRIEMEL Nov. 26, 1940.

STRIP FEEDING FOR SOUND AND SOUND PICTURE SYSTEMS Filed April 9, 193'! 3 Sheets-Sheet 2 INVEN TOR H. F R/E MEL A T TORNE Y Nov. 26, 1940'. Y H. FRIEMEL I 2,223,033

STRIP FEEDING FOR SOUND AND SOUND PICTURE SYSTEMS Filed April 9, 1937 3 Sheets-Sheet 3 FIGS lNl/ENTOR H. F R/EME L A TTORNE V Patented Nov. 26, 1940 UNITED STATES STRIP FEEDING I03 SOUND AND SOUND PICTURE SYSTEMS flansl'riemeLBes-limGermany, liangfilmflelelllchaftmit adsnorte beoehrankier Haltung,Balin,Germany.aGermanm Application April 0, 1987,

In Germany lclaims.

This invention relates to film feeding devices for sound and sound picture systems in which the take-up reel is initially driven before the other film feeding devices.

The invention provides an arrangement of apparatus for initially operating the take-up reel and for starting other film feeding devices by a switch associated with the film which is operated when the film is being wound properly on the take-up reel and for stopping the operation of the other film feeding devicm whenever proper winding of the film on the take-up reel ceases.

The application of devices according to the invention to sound and sound picture apparatus is of particular advantage in suppressing velocity variations produced by the uneven load in winding the film on the take-up reel. Many forms of friction clutches have been developed for the take-up reel in an effort to minimize these variations as the diameter of the film on the reel becomes greater and the film load changes but this is a dimcult problem where the take-up reel and other film feeding devices are driven by the same motor. It is further true that regardless of the devices used there are inherent difilcult obstacles to overcome in suppressing the film load variations ordinarily produced in taking up the film and while the separate drive for the takeup reel is one solution there are additional problems which present themselves in controlling two film drives. Assuming, for example, that an electric motor is used for separately driving the take-up reel, means must be found for controlling the successive starting of two motors in a manner to have the film take-up and the film feeding properly related. The take-up reel motor should not cause the film to be taken up too rapidly before the second motor is started but also the film must assuredly be winding properly on the reel before the second motor is started. During the following period when these motors are coming up to normal running speed there is ordinarily a tendency toward what is termed motor hunting and, consequently, the motor design and the time functions of the controlling switches must be such as to prevent hunting between motors. Also during this period and later, when the film is fed at normal velocity, the speed of the take-up reel motor must be regulated entirely by the load thereon. This load is considered as a single factor but is actually composed of the take-up film load which is variable, a constant load placed on the film by the film feeding sprockets and a secondary variable load which Serial No. 1351. M1 30, 1938 'mustbeplacedonthefilmthroughanelsstic member preferably associated with mechanism for operating electrical contacts. With a leparate drive a solution of this problem is possible only if the mechanical and/or electrical charac- 5 teristics of the take-1m reel motor, elastic member and controlling devices are properly coordinated.

The object of this invention is therefore to provide an accurate and economical means 10 whereby the operation of the separate units is properly controlled to substantially eliminate the uneven load of the take-up reel and to provide a safety device at all times for stopping the film feeding devices whenever various well-known film l8 feeding troubles are encountered, such for example as a break in the film.

In one embodiment of the invention one motor is used for operating the take-up reel and a second motor is used for operating the remaining film feeding devices of the sound picture system. The take-up reel motor is started by a manually operable switch and the second motor is started by a film operated switch located between the last film feeding roller and the take-up reel. The action of the latter switch is such that when a certain film length is reached between the roller and the take-up reel the driving motor for the roller is started. The take-up reel motor as later described may be of a type which responds as to speed in accordance with the load placed thereon and thus may be carefully regulated by the load as the motor which drives the film feeding devices comes up to speed. An elastic member associated with the film operated switch assists in the control of the take-up reel motor. At any time that the film is not being wound properly upon the take-up reel the film length between the last feeding roller and the take-up reel becomes greater causing the switch to operate in the reverse direction for opening the electrical circult for the second motor. This also becoms a safety factor to prevent trouble in the case of a broken film or when other well-known difficulties occur.

The invention will be better understood from the following description taken in combination with the accompanyi drawings.

In the illustrated embodiment, Figs. 1A and a 1B illustrate the principle involved in the invention;

Figs. 2 and 3 illustrate an arrangement of the invention using mechanical devices to prevent hunting in the motor controlled by the switch, 5

Fig.2beingpartlyinsection.andFig. Ibeingin perspective.

Figs. 4 and I illustrate a sound recorder having one form of the film controlled switch therein. 5 Fig. I shows the operating mechanism of Fig.

8 applied to an alternative type of switch.

Fig. 'I shows structural details of the apparatus shown in I'll. I.

InFlg. 1A thetake-upreel I isdrivenbyon 10 electric motor and the roller or sprocket I is driven by a second electric motor. The film 1" is wound on the take-up reel in the direction indicated by the arrow. Between the takeupreelandthefilm driving roller I, thefilm passestwoi'ollersIandI. TherollerIis spatially fixed and rotated around the shaft I. TheshaftI hasarolier I associated therewith through the lever arm I, the roller being able to rotate freely on its shaft II, which is connected to the lever arm I. The positionsoftherollerland leverarm ldepend upon the length of film loop between the take-up reel I and the driving reel I. The roller I may assums, various positions as lever I swings about the'axis I of the roller I between the limit of stops I and I. This movement of lever I as controlledbythcfilmisemployed foropcratingan electric switch.

Fig. 13 illustrates another simple embodiment of the invention. The take-upreel is likewise denotedby I andthefilmfeedlngrollerbyl,asin Fig. 1A. 'Ihe roller I is secured to the lever arm I which is rotatable about the shaft I. when the film loop increases, the roller I and lever armlmoveinthedirectionofthearrowbetween the stops I and I. This motion can again be utilised for the operation of an electric switch. when the film loop is increased, the roller I follows the film under the control of a spring II, whichexertsafonceonleverarmlcontraryto the force exerted by the film through the roller I. Thisspringisnotshowninl 'lg. lAbutmay be used in the combination to position the rollers or it may be replaced by any other well-known means to produce this effect. for example, by a weight. 1 In Figs. 2 to I the switch contacts are shown in combination with mechanical devices for starting and stopping the motor, whereby after starting the m tor, considerable variation in the tightness o the film is permitted before again stopping the motor. 'Ihis provides an elastic member between the film feeding roller I and u the take-up reel and also prevents hunting which might occur with the arrangement shown in Figs. 1A and 13. Consideration of this condition will expedite the understanding of the arrangement shown in Figs. 2 and 8, for example, if the motorforthetake-upreel I isstarted.thefilml" will be shortened and the lever arm I will press against the stop I. In this'position an electric contact is actuated for starting the motor for driving roller or sprocket I. If immediately 5 thereafter the length of film between roller I and the take-up reel I would become somewhat greater, the motor for the roller I would be stopped. The take-up reel motor would then again shorten the film loop which would again operate the (0 switch for starting the motor. Hence hunting effects may occur, which are positively eliminated by the invention as arranged in Figs. 2, 3', 4 and 5. InFlgaIandIcorrespondingpartsare designated by the same reference numerals as in 75 Figs. 1A and 1B. The arrangement of the c rcult and film driving mechanism including the motorsmaybeasshowninFlgs. 4,5and7. In the latter figures the path of the film may be traced from the delivery reel III to the lower sector of. driving sprocket I, guide rollers II and II, sound roller II, upper sector of driving sprocket I, over roller I and under roller I of the switching mechanism, and thence to the takeup reel I. Motor II is shown for driving the take-up reel I through suitably disposed gears and a chain drive as disclosed in Fig. 5. Motor II is shown for driving the film feedingmechanism through shaft II and an appropriate set of gears, shown in Fig. 7. Referring to Fig. 7 it may be seen that shaft II drives a worm II cooperating with a worm wheel II mounted on a countershaft II. The shaft II supplies rotary power to sprocket I which is rigidly secured thereto. A source of current II is connected to the switching circuit arranged with a manually operable switch II for actuating motor II and a film operable switch II for actuating motor II. The switch II is a modification of the switch shown in Figs. 2 and 3 and will be described after an understanding of the switching mechanism of Figs. 2 and 3 has been given.

In Figs 2 and I the roller I is arranged to freely rotate on the shaft I. The lever arm I is rigidly fastened to the shaft I and also supports a spindle II on which the roller I may revolve freely. As shown in Fig. 2 the film passes under the roller I and over the roller I. The shaft I is held by a standard II fastened to the frame of the recorder and can freely rotate in a bearing II mounted in this standard. At the other side of the standard there is arranged a spiral spring II with its inner end rigidly connected to the shaft, while its outer end is attached to the standard II. This spring tends to turn the roller I against the force exerted on the latter by the film. Lever arm II is rigidly connected to the extreme end of shaft I. The switch arms II and II are rigidly fastened to shaft II. The switch II shown as a mercury switch is held in a position by arm II which allows it to urn with the shaft II for closing and opening contacts. The shaft II rotates in the standard II, which is fastened to the frame. According to the foregoing, it is apparent that the roller I may swing about the axis of shaft I under the control of the film loop and thus rotate shaft I and lever arm II. In order to convert the rotary movements of the control shaft I into intermittent switching movements of the shaft II, the two levers II and II are connected by a spring II. As will be explained in the following, when the rotary movement of the shaft I is clockwise, the rotary movement of the shaft I1 is counter-clockwise. This will be better understood by referring to Fig. 3. It may be assumed that with both motors stationary, the arm I rests against the stop I and the switching lever II rests against the stop II. When the motor II for the take-up reel I is started by the operation of manual switch II shown in Fig. I, the film shortens itself and the roller I moves in the direction of the arrow II into position a. By this rotation the lever II moves into the position a. The spring II which connects the two lever arms II and II is tensioned but the lever arm II, which is rigidly con-.

nected to shaft II, cannot rotate in the direction of the spring pull on account of stop II. with the further rotation of the roller I in the direction of the arrow II, the position b is reached.

a,aas,oss

,At the same time the lever I4 reaches the position b. At this moment the spring II is tensioned with maximum force as shown in Fig. 3. Now if the lever II is moved only a trifle beyond the position b, the switch arm II is moved in the direction of the arrow 21 under the force of the spring II. The switch arm II rotates to the stop 2i and in doing so rotates the shaft I1 and the member 2I, which has the mercury switch II mounted thereon. The rotation of the shaft I! will thus cause the mercury switch II to complete the circuit for starting the driving motor II. This circuit extends from the source of power I! through a flexible lead wire attached to electrode II, a body of mercury (which has now assumed a position so as to cover electrodes I8 and 14), electrode ll operating windings of motor II, and thence by return conductor to the power source IS. The starting of the driving motor II for sprocket 2 may momentarily increase the size of the film loop and thus move the roller I contrary to the direction of the arrow 22 out of position b. This movement, however, does not bring about a change in position of the switch II. As illustrated in the drawings, it is necessary for the roller I and the lever II to rotate through an are greater than 70 degrees to again change the position of the switch arm II for opening the switch contacts which would stop the motor II. There is thus a time interval between the point-to-point movement of the lever I4 and the point-to-point movement of the switch arm II. As the motor II comes up to speed, the roller I is slowly moved out of the position b in the direction of the arrow 22 toward the position c. The roller I may move in this direction until the lever arm I meets the stop I. Since the lever arm I4 is rigidly connected to the shaft I, it moves to position c when the roller I moves into position c. It is possible to change these limits by changing the position of stop I.

As herein set forth a spring I 0 is introduced in the switch between the roller 2 and the take-up reel. This spring not only serves in the proper operation of the switch members but acts in the capacity of an elastic load to assist in balancing the driving torque of motor III as the film load changes and assists in the control of the speed of this motor. The motor II for rendering this character of service may be a small three-phase induction motor designed to permit slip between the rotating field and the armature in order that its speed may be regulated within desired limits by the load. In order to produce the desired regulation, the torque of motor 60 may be about equal or slightly greater than required to carry the normal load with the film roll diameter small and the roller I in position b, the spring I0 being tensioned accordingly. When the take-up reel is required to run at a lower speed an increased tension of spring II is used to balance the torque of motor III and consequently cause a greater slip between the field and armature.

A three-phase motor is of course only one of many varieties of motors which may be designed to function properly in this service.

If we now assume that the take-up reel motor 60 no longer functions properly or that some defect arises in the winding operation, the film loop will at once become greater, which causes a movement of the roller I toward its normal position. The roller I moves under the control of the film from position c to position b and into position a. This causes the lever arm II to also move into position a. Not until this position is reached will the spring I. between the lever arm I4 and switch arm II cause-the switch arm II to be rotated back to the stop 2|. There is consequently a minimum rotation of approximately 72 degrees before the switch is opened. The movement of the switching arm II rotates the shaft II in a clockwise direction, thereby opening the contacts of switch II to stop the motor II.

The switch I shown in Fig. 4 operates in the same manner and on the same principle as that shown in Figs. 2 and 8 with the exception that a contact switch is substituted for the mercury switch and a switch operating arm II is substituted for the arm 20. Arm ll cooperates with mechanical contacts 32 and II which are normally maintained in an open position by virtue of the resilience of spring member 23. Obviously, these mechanical contacts will be closed and opened with the same timing and with the same snap action which occurs when the mercury switch is used. It will be noted that the rollers and lever arms bearing the same numerals as Figs. 2 and 3 are shown in the same relation. When the lever arm II has rotated through an arc of over degrees, switch arm II is moved by the pull of spring II to the stop 2| for causing closure of contacts 32 and a to start the motor II over a circuit identical with that previously described for the mercury switch except that in this instance, the mechanically operated contacts replace the electrodes bridged by the fluid mercury. Switch arm 3| is retracted in the same manner as arm 28 and in this case opens contacts 82 and 38 to stop motor II.

It is not the intention to limit the invention to the specific embodiment disclosed since it can be used in many ways for operating or switchng apparatus electrically according to the condition of a film loop. For example, a single motor may be used which may initially drive the take-up reel and also drive the other film feeding devices through a mechanical or magnetic couplin which is operated under the control of the film actuated switch.

What is claimed is:

1. In a strip feeding system, a strip-pulling device, a motor for driving said strip-pulling device, a second motor for driving other strip feeding mechanism, a switch for starting the strippulling device motor, and a second switch between the feeding mechanism and the strippulling device operated by the action of the strip in passing to the strip-pulling device for Starting said second motor.

2. In a strip feeding system, a strip-pulling device, a motor for driving said strip-pulling device, a second motor for driving other strip feeding mechanism including a feeding roller, a switch for starting the strip-pulling device motor and a second switch between the feeding roller and the strip-pulling device operated by the strip in passing to the strip-pulling device for starting and stopping said second motor.

3. In a strip feeding system having one motor for driving a strip-pulling device and a second motor for driving other strip feeding mechanism including a feeding roller, a switch for starting the strip-pulling device motor, electrical switching contacts for controlling the second motor, and a toggle switch arm actuated by the strip in passing to the strip-pulling device for closing and opening said contacts.

1 the strip-pulling device for operating said switch srm.

5. In o strip feeding system, a strip-pulling device, a motor for driving said strip-pulling device, 1 second motor for driving other strip reeding mechnnism including 1 feed roller, 1 switch for starting the strip-pulling device motor and a dim operated switch for controlling the other 5 motor positioned between said teed roller end the strip-pulling device comprising switching contacts. I lever srm moved by the feeding of the strip to the strip-pulling device, end a switch arm moved by the lever nrm for actuating sold 10 contacts. 

